Operation modifying means for a control structure



July 17, 1934. M. E. HENNING 1,966,720

OPERATION MODIFYING MEANS FOR A CONTROL STRUCTURE Original Filed Jan.27, 1930 i afented July 17, 1934 UNETED STATES OPERATION MODIFYING MEANSA CONTROL STRUCTURE Malcolm E. Henning,

Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines,Iowa,

a corporation of Iowa Original application January 27, 1930, Serial No.423,677. Divided and this application May 11,

1931, Serial No. 536,347

2 Claims.

The object of my invention is to provide an operation modifying meansfor a control structure which is simple, durable and comparativelyinexpensive to manufacture.

The present application is a division of my copending application on acontrol switch structure, Serial No. 423,677, filed January 27, 1930.

Another object of my invention is to provide a specific type ofmodifying means for a movable member of an automatic control structure,such as a temperature or pressure operated switch structure.

More particularly, it is my object to provide a modifying means in theform of a spring adapted to act upon the movable member and beingadjusted by a nut, which is threaded on a control shaft, the shaft beingrotatably and non-slidably mounted and the nut being held againstrotation by the spring.

With these and other objects in view my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims, and illustrated in theaccompanying drawing, in which:

Figure l is a front elevation of a control structure showing myoperation modifying means applied thereto.

Figure 2 is an enlarged sectional view on the line 2--2 of Figure 1.

Figure 3 is a sectional view on the line 3-3 of Figure 2; and

Figure 4 is a perspective view of the operation modifying means, theparts being shown separated.

On the accompanying drawing, I have used the reference numeral 10 toindicate a switch housing. Within the switch housing 10, switch contacts12 and 14 are provided, the contact 14 being carried by a switch arm 16.The switch arm 16 is pivoted to a pin 18, one end of which extends intothe housing 10 and the other end of which is supported by a supportingbar 20. The supporting bar 20 is secured to the switch housing 10 byscrews 22, which are shown in section, having been cut off so that mostof the supporting bar 20 may be omitted to more clearly show the detailsof the construction.

A temperature or pressure operated bellows is indicated at 24. Thebellows 24 has an operating pin 26 secured to the head 28 of thebellows. The pin 26 engages a bellows lever 30, which is pivoted to apin 32, supported in a manner similar to the pin 18.

Movement of the bellows 24 and the bellows lever 30 is opposed by a mainspring 34. The main spring 34 is suitably adjustable as to tension forcausing operation of the switch contacts l2 and 14 to open and closedposition at predetermined degrees of temperature or pressure within thebellows 24.

The bellows lever 30 is operatively connected with the switch arm 16 bya link or bail 36, whereby movements of the lever 30 are imparted to thearm 16.

My operation modifying means comprises generally a leaf spring 38,control shaft 40, control'knob 42 and an adjusting nut 44. The leafspring 38 is provided with a foot 38a, per- 70 forated as indicated at46. By means of rivets 48, extending through the perforations 46, theleaf spring 38 is connected with the bellows lever 30 for modifying theoperation thereof.

The control shaft 40 is suitably joiunalled in a bearing 50 in the wallof the switch housing 10 and is held against longitudinal movement inthe following described manner.

A threaded portion 52 is formed on the control rod 40 and terminates ina shoulder 54. The shoulder 54 engages a washer 56, which in turnengages one end of the bearing 50. The control knob 42 is secured to thecontrol shaft 40 by a set screw 58. The control knob engages the otherend of the bearing 50.

A friction washer is provided to prevent rotation of the control shaft40 except when the control knob 42 is engaged and rotated by theoperator.

Threadedly mounted on the screw-threaded portion 52 of the control shaft40 is a nut 44. The nut 44 is provided with a pair of grooves 64 intowhich arms 66 of a forked end of the leaf spring 38 extend. Thus, asclearly shown in Figure 3, the nut 44 is held against rotation by thespring 38, but upon rotation of the control shaft 40, longitudinalmovement is imparted to the nut 44 for thus swinging the leaf spring 38and modifying the action of the bellows lever 30.

A head or collar 68 may be formed on or secured to the control shaft 40to prevent excessive rotation of the control shaft in one direction, thewasher 60 being engaged by the nut 44 when traveling in the otherdirection for thus limiting the rotation of the knob 42.

From the foregoing description, it is apparent that rotation of the knob42 in one direction will tension the spring 38 to assist the bellows 24and rotation in the opposite direction will have the reverse effect, oroppose the bellows. Thus the operation of the control structure can bemodified independent of the initial adjusting spring 34.

Some changes may be made in the construction and arrangement of theparts of my device Without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by my claims, any modifiedforms of structure or use of mechanical equivalents, which may bereasonably included within their scope.

I claim as my invention:

1. In a control structure, a pivoted control member and means formodifying the action thereof comprising a leaf spring attached thereto,a control shaft rotatably and nonsl idably mounted, a nut threadedthereon, said nut having a pair of oppositely disposed groovestransversely arranged relative to the axis of the control shaft, saidspring having a forked end engaging in said grooves.

2. In a device of the class described, a pivoted member, a spring actingthereupon and means for adjusting the tension of said spring comprisinga control shaft rotatably and nonslidably mounted, a nut threadedthereon said nut having a pair of flattened surfaces said spring havinga forked end engaging said surfaces to thereby prevent rotation of saidnut.

MALCOLM E. HENNING.

